Method of producing silicon-steel sherts



V. B. BROWNE.

METHOD OF PRODUCING SILICON STEEL SHEETS.

APPLICATION FILED JUNE 21, I919.

1,393,889.- Patented Oct. 18, 1921.

IN MENTOR W/TNESSES VERE B. BROWNE, OF TARENTUM, PENNSYLVANIA.

METHOD OF PRODUCING SILICON-STEEL SHEETS.

Application filed June 21.

To allwhomz'tmcy concern: 7

Be it known that I, VERE B. BROWNE, a citizen of the United States, and a resident of Tarentum in the county of Allegheny and State of l ennsylvania, have made a new and useful Invention in Methods of Producing Silicon-Steel Sheets, of Whichthe following is a specification.

This invention relates to a method of producing sheets of low hysteresis silicon steel having a uniform grain size.

In building up the laminated structures of electrical apparatus having alternating magnetic fields it is now customary to use sheets of silicon steel, and, in order to obtain in such structures suitable magnetic permeability and suitable hysteresis action with a minimum of eddy losses it is only possible to utilize a portion of the sheets made under any olf the processes with which I am familiar. Under the present processes of rolling such silicon steel sheets it is impossible to obtain sheets of uniform quality. Some of the sheets will have higher magnetic and electrical values than others, and this occurs in sheets from the same pack as well as in sheets from different packs. The loss, therefore, is considerable. It is believed that the position of the sheets in the pack during the finishing pass or passes and the temperature at which they are rolled determines the grade or quality of the finished sheets; the sheets on the inside of a pack are superior to those on the outside.

Under the present practices a run over pack of silicon steel sheets is produced from one or more sheet bars by suitable heating, rolling, pairing, matching, doubling or otherwise manifolding This pack is usually four ply and approximately the full length and thickness of the finished pack. The run over pack is usually doubled, given the finishing heat in the sheet furnace and then rolled out to length. The finished pack is then sheared, opened and suitably annealed. According to my new process silicon steel sheets maybe rolled according to any usual method to a suitable or definite thickness. The pack is then sheared and opened and the sheets sheared to a suitable size. The sheets are then singly inserted into a pack which has reached a stage in its manufacture rior to the final heat, a stage at which the sheets are considerably thicker than the sheets to be inserted.

The pack including the inserted sheet or Specification of Letters Patent.

Patented Oct. 18, 1921. 1919. Serial No. 305.923.

sheets is then rolled to such a length as will glve to the inserted sheet or sheets the desired thickness thereafter the sheets are separated and the silicon steel sheet or sheets su tably annealed so as to promote the deslrecl gram growth.

have found that by thus treating the s1l1 con steel sheets I can obtain an even and un1form gram of the desired size, after anneahng, and that practicall all of the sheets treated in this manner will be of the highest quality or grade. The sheets will be practically free from scale, and laminated structures built up therefrom will be uniform throughout so far as magnetic permeability and hysteresis action are concerned and the eddy losses therein will be of a minimum value.

It is preferable to insert the sheets singly at or near the center of the pack but favorable results have been obtained by inserting two or more sheets in a pack, separating the single sheets thus inserted by one or more of the heavier sheets making up the pack.

- The single sheet of drawings forming art of this application diagrammatically ilustrates such a built up pack. I

After the pack is built up it is given the final heat necessary for the finishing pass or passes of the inserted sheet or sheets and then preferably rolled quickly. The pack in the final heat is preferably raised to a temperature above the recalescent point so that the inserted sheets on account of being protected are finished at approximately the temperature of recalescence. Satisfactory results may be obtained with other temperatures if the pressure in the final pass or'passes is such, that, in connection with the temperature reached the desired grain (as to uniformity and size) in the finished sheets, after annealing, will be obtained.

The pack in which thesilicon steel sheets are inserted may be made up of sheets of steel having dissimilar characteristics to the silicon steel so that under the rolling pressure and temperature of the finishing pass or passes, welding thereof with the silicon steel sheets will not occur.

Having thus described my invention what I claim is- Y 1. The method of r'olling'low hysteresis action silicon steel sheets, which consists in producing a'partially finished sheet of silicon steel, in inserting said sheet within a pack the sheets of which have been finished heating said other pack to a less extent, in raising the pack with the inserted sheets to about the temperature of recalescence, in rolling said ack to such length as will give the desire thickness to the inserted sheet, in removing said sheet from said pack and then in annealing said sheet.

2. The method of rolling low hysteresis action silicon steel sheets, which consists in producing a pack of partially finished silicon steel sheets, in shearing and opemng said pack, in producing another pack of sheets finished to a less extent, then inserting a sheet or sheets from the first pack at or near the center of the other pack, then in to; about the temperature of recalescence, then in rolling said other pack to such length as will give the inserted sheet or sheets the desired thickness, in removing the inserted sheet or sheets from the other pack and then in annealing the removed sheets.

3. The method of. rolling low hysteresis action silicon steel sheets, which consists in hot rolling a sheet of silicon steel of a definite thickness, in inserting said sheet within a pack of sheets finished to a less extent and before shearing, in heating said pack, in rolling the same to length and then in remOVlI ig the inserted sheet.

4. he method of rolling low hysteresis action silicon steel sheets, which consists in sheet when finished, in inserting said sheet within a pack of sheets finished to a less extent, in heating said pack to rolling temperature, in rolling said pack to such length as will give the inserted sheet the desired thickness, in removing the inserted sheet from the pack and then in annealing said sheet.

6. The methodof rolling low hysteresis action silicon-steel sheets, which consists in producing a sheet of silicon steel, in inserting said sheet within a pack of dissimilar steel finished to a less extent, in heating said pack, in rolling the same to such length as will give the desired thickness to the inserted sheet and then in annealing the inserted sheet.

In testimony whereof, I have hereunto subscribed my name this 19th day of June,

VERE B. BROWNE 

